1. Field of the Invention
The present invention relates generally to medical apparatus and, more particularly, to methods and apparatus for cutting and removing soft or hard tissue by aspiration.
2. Description of Related Art
Turning to FIG. 1, a prior art optical cutter includes a fiber guide tube 5, a water line 7, an air line 9, and an air knife line 11 for supplying pressurized air. A cap 15 fits onto the hand-held apparatus 13 and is secured via threads 17. The fiber guide tube 5 abuts within a cylindrical metal piece 19. Another cylindrical metal piece 21 is a part of the cap 15. The pressurized air from the air knife line 11 surrounds and cools the laser as the laser bridges the gap between the two metal cylindrical objects 19 and 21. Air from the air knife line 11 flows out of the two exhausts 25 and 27 after cooling the interface between elements 19 and 21.
The laser energy exits from the fiber guide tube 23 and is applied to a target surface of the patient. Water from the water line 7 and pressurized air from the air line 9 are forced into the mixing chamber 29. The air and water mixture is very turbulent in the mixing chamber 29, and exits this chamber through a mesh screen with small holes 31. The air and water mixture travels along the outside of the fiber guide tube 23, and then leaves the tube and contacts the area of surgery.
Other prior art devices include optical cutting systems utilizing the expansion of water to destroy and remove tooth material, such as disclosed in U.S. Pat. No. 5,199,870 to Steiner et al. This prior art approach requires a film of liquid having a thickness of between 10 and 200 xcexcm. U.S. Pat. No. 5,267,856 to Wolbarsht et al. discloses a cutting apparatus that requires water to be inserted into pores of a material and then irradiated with laser energy. In both patents the precision and accuracy of the cut is highly dependent upon the precision and accuracy of the water film on the material or the water within the pores.
Devices have existed in the prior art for utilizing laser energy to perform liposuction and body contouring procedures, wherein laser energy facilitates the separating of soft tissue from a patient in vivo. U.S. Pat. No. 4,985,027 to Dressel discloses a tissue remover that utilizes laser energy from a Nd:YAG to separate tissue held within a cannula, the contents of which are expressly incorporated herein by reference. Use of the Nd:YAG laser for in vivo tissue removal is in some ways inefficient, since the energy from the Nd:YAG laser is not highly absorbed by water. Further, the Nd:YAG laser and other lasers, such as an Er:YAG laser, use thermal heating as the cutting mechanism. Adjacent tissue can be charred or thermally damaged and, further, noxious and potentially toxic smoke can be generated during the thermal cutting operations performed by these prior-art devices.
Devices also have existed in the prior art for performing endoscopic surgical procedures, wherein one or more catheters or cannulas are inserted through a small opening in a patient""s skin to provide various working passageways through which small surgical instruments can be advanced into the patient during surgery. Specific endoscopic applications include arthroscopic surgery, neuroendoscopic surgery, laparoscopic surgery, and liposuction. Arthroscopic surgery refers to surgery related to, for example, joints such as the shoulders and knees. One prior-art device, which has been used during the implementation of an arthroscopic surgical procedure is an arthroscopic shaver. The arthroscopic shaver entails the application of a spinning tube-within-a-tube that concurrently resects tissue while aspirating debris and saline from within the operative site. One such arthroscopy system is the DYONICS.RTM. Model EP-1 available from Smith and Nephew Endoscopy, Inc., of Andover, Mass. Cutting with such an instrument is obtained by driving the inner tube at a high speed using a motor. Surrounding the tubular blade is an outer tubular membrane having a hub at its proximal end adapted to meet with the handle. Performing an arthroscopic procedure with a high-speed rotary shaver such as the one mentioned above may result in extensive trauma to the tissue and blood vessel laceration.
The present invention discloses an electromagnetically induced cutting mechanism, which can provide accurate cutting operations on hard and soft tissues, and other materials as well. Soft tissues may include fat, skin, mucosa, gingiva, muscle, heart, liver, kidney, brain, eye, and vessels, and hard tissue may include tooth enamel, tooth dentin, tooth cementum, tooth decay, amalgam, composites materials, tarter and calculus, bone and cartilage.
In accordance with the present invention, an electromagnetically induced cutter is used to perform surgical procedures, using cannulas and catheters, also known as endoscopic surgical procedures. Endoscopic surgical applications for the electromagnetic cutter of the present invention include arthroscopic surgery, neuroendoscopic surgery, laparoscopic surgery, liposuction and other endoscopic surgical procedures. The electromagnetically induced cutter is suitable to be used for arthroscopic surgical procedures in the treatment of, for example: (i) torn menisci, anterior cruciate, posterior cruciate, patella malalignment, synovial diseases, loose bodies, osteal defects, osteophytes, and damaged articular cartilage (chondromalacia) of the knee; (ii) synovial disorders, labial tears, loose bodies, rotator cuff tears, anterior impingement and degenerative joint disease of the acromioclavicular joint and diseased articular cartilage of the shoulder joint; (iii) synovial disorders, loose bodies, osteophytes, and diseased articular cartilage of the elbow joint; (iv) synovial disorder, loose bodies, ligament tears and diseased articular cartilage of the wrist; (v) synovial disorders, loose bodies, labrum tears and diseased articular cartilage in the hip; and (vi) synovial disorders, loose bodies, osteophytes, fractures, and diseased articular cartilage in the ankle.
The electromagnetically induced cutter of the present invention is disposed within a cannula or catheter and positioned therein near the surgical site where the treatment is to be performed. In accordance one aspect of the present invention, a diameter of the cannula or catheter is minimized to reduce the overall cross-sectional area of the cannula or catheter for the performance of minimally invasive procedures. In accordance with another aspect of the present invention, a plurality of catheters is formed together for various purposes. For example, in arthroscopic knee surgery, one cannula is configured to incorporate the cutting device and suction, and a separate cannula is configured to incorporate the imaging system that monitors the treatment site during the procedure. In accordance with yet another aspect of the present invention, the suction, cutting device and imaging device are all incorporated within the same cannula. Another aspect of the present invention provides for an additional third cannula for supplying air to the treatment site.
The electromagnetically induced cutter of the present invention is capable of providing extremely fine and smooth incisions, irrespective of the cutting surface. Additionally, a user programmable combination of atomized particles allows for user control of various cutting parameters. The various cutting parameters may also be controlled by changing spray nozzles and electromagnetic energy source parameters. Applications for the present invention include medical procedures, such as arthroscopic surgery, neuroendoscopic surgery, laparoscopic surgery, liposuction and dental, and other environments where an objective is to precisely remove surface materials without inducing thermal damage, uncontrolled cutting parameters, and/or rough surfaces inappropriate for ideal bonding. The present invention further does not require any films of water or any particularly porous surfaces to obtain very accurate and controlled cutting. Since thermal heating is not used as the cutting mechanism, thermal damage does not occur. Adjacent tissue is not charred or thermally damaged and, further, noxious and potentially toxic smoke is attenuated or completely eliminated.
The electromagnetically induced cutter of the present invention includes an electromagnetic energy source, which focuses electromagnetic energy into a volume of air adjacent to a target surface. The target surface may comprise fatty tissue within a cannula, for example. A user input device specifies a type of cut to be performed, and an atomizer responsive to the user input device places a combination of atomized fluid particles into the volume of air. The electromagnetic energy is focused into the volume of air, and the wavelength of the electromagnetic energy is selected to be substantially absorbed by the atomized fluid particles in the volume of air. Upon absorption of the electromagnetic energy the atomized fluid particles expand and impart cutting forces onto the target surface.
The electromagnetically induced cutter of the present invention can provide an improvement over prior-art high-speed rotary shavers, such as the above-mentioned arthroscopic shaver, since the electromagnetically induced cutter of the present invention does not directly contact the tissue to cause trauma and blood vessel laceration. Instead, cutting forces remove small portions of the tissue through a process of fine or gross erosion depending on the precision required. This process can be applied to precisely and cleanly shave, reshape, cut through or remove cartilage, fibrous cartilage, or bone without the heat, vibration, and pressure associated with rotary shaving instruments. The system can be used without air and/or water, in order to coagulate bleeding tissue. In accordance with another application of the electromagnetic cutter, a spray of water is the carrier of an anti-coagulant medication that could also contribute to tissue coagulation.
Other endbscopic applications for the electromagnetically induced mechanical cutter include neurosurgical and abdominal surgical applications. In neurosurgery, the electromagnetically induced mechanical cutter is suited for removing brain tissue lesions, as well as for the cutting of various layers of tissue to reach the locations of the lesions. The entire method of creating an access through the scalp into the bone and through the various layers of tissue that protect the brain tissue can be accomplished with the electromagnetically induced mechanical cutter of the present invention.